ME’scopeVES – Packages

ME’scopeVES – Packages

VT-620 Visual ODS

VT-620 Visual ODS™ is the base for all other ME’scope Packages

An animated ODS shows how your machine or structure is moving in slow motion. By animating the ODS’s of a structure, you can see what can’t be seen any other way; a structure’s overall motion and the motion of one part relative to another. Excessive vibration levels and loose or damaged parts are easily identified from an animated ODS display.

Visual ODS lets you see how a machine or structure is moving by animating ODS’s directly from a set of time of frequency domain experimental data.

As an example of the practical use of Visual ODS, a blower fan located on the roof of a building was experiencing severe vibration, throwing off belts, and creating high noise and vibration levels throughout the building. All attempts to balance the fan had not solved the problem.

A set of ODS data was taken while the fan was running, using a 2-channel analyzer with a tachometer signal. A set of Peak & Phase data at the operating speed of the motor was acquired. The animated ODS showed that the base of the motor at the end opposite the belt was moving out of phase with the motor. Removing some paint from the base of the motor revealed a previously undetected crack in the motor mount. After repairing the crack, the fan was re-balanced and the severe vibration and noise problem was solved.

Visual ODS™ Features:

Interactive 3D Structure Model

  • Create 3D structure models for displaying ODS’s in animation, using Points, Lines, Surface Triangles, and Surface Quads
  • No limits on the model size
  • Each Point on the 3D model has its own local measurement axes (in Rectangular, Cylindrical, Spherical or Machine coordinates). Measurement axes are graphically oriented at each Point to match the sensor measurement directions
  • The animated display of all un-measured Points & directions is interpolated from the animated motion of nearby measured Points & directions
  • Light sources are used to make solid models look more realistic
  • Photo realistic models (3D models made from digital photographs) provide more realistic animations
  • Transparent surfaces allow better clarity of the motion of hidden portions of the structure
  • 2D Structure model outlines can be traced from digital photographs or drawings.
  • 2D models can be extruded or revolved to create 3D models
  • On screen sizing, shaping, positioning and rotation of all drawing objects
  • Create Substructures of selected Points, Lines and Surfaces to break complex models into components with simpler geometries. Substructures can also be moved, hidden, and made transparent for better clarity
  • Drawing Assistant. Rapidly build 3D models using a library of editable and user-built Substructures
  • The 3D model can be displayed in Quad View (X, Y & Z and user interactive 3D View), or in a single View
  • Zoom, Pan, Rotate, and change the Perspective distance from the model
  • Cut, Copy and Paste drawing objects
  • Copy and paste properties in the drawing objects spreadsheet
  • The speed of rotational Substructures is synchronized with the speed of order-tracked ODS’s
  • Imports Structure models from over 14 different third party disk files

Time and Frequency Domain Measurements

  • Data imported from most popular single or multi-channel analyzers, recorders, data acquisition systems and portable data collectors
  • All popular types of time and frequency domain measurements can be imported
  • No limits on the number of measurements or the number of samples per measurement
  • Measurements can be displayed in Real, Imaginary, Magnitude (Linear, Log, dB), Phase, CoQuad (Real & Imaginary), Bode (Magnitude & Phase), Nyquist and Orbit Plots
  • Measurements can be displayed in Row/Column, Strip Chart, Waterfall, Overlaid or Overlaid by DOF, and Color Map formats
  • The measurement display can be Zoomed & Scrolling
  • Line, Peak and Band Cursors can be displayed on each measurement
  • All graphics can be copied to the Clipboard either as a Bitmap or Metafile
  • All spreadsheet properties can be copied and pasted using the Windows Clipboard
  • Imports Peak & Phase data for animation of order-based ODS’s
  • Imports measurement data from over 40 different third party disk files

Animated Display of ODS’s & Mode Shapes

  • Interactive sweep, dwell, or static display of ODS’s directly from time or frequency measurements, using the Line, Peak or Band Cursor
  • Interactive sweep, dwell, or static display of mode shapes or ODS’s from a shape table
  • Shape Interpolation. Geometrically weighted calculation of shape values for unmeasured DOFs using data from nearby measured DOFs
  • Comparison display of ODS’s from two Data Blocks or Shape Tables in Side-by-Side or Overlaid format
  • Animated shape display using Deformation, Arrows, Text values, or surface Contour Colors with Node Lines
  • Animation with persistence for displaying orbit data at each Point.
  • Hidden line and transparent surface display for greater clarity
  • Digital Movies (Windows WMF’s) can be created during shape animation. Recorded animations can be imbedded in MS Power Point presentations.
  • ODS’s and mode shapes can be imported from over 10 different third party disk files

Macro-programs With Hotkeys

  • Macro-programs make it easier to execute repetitive tasks, and to execute a sequence of commands for demonstration purposes.
  • A macro-program is a spreadsheet of ME’scope window names and commands. Each line of a macro-program contains an ME’scope data file window and a command to be executed in that window
  • When a macro-program is executed, all commands in the macro are executed in sequence from top to bottom
  • Hot Keys. Any macro-program can be executed by pressing its Hotkey on the ME’scope menu bar

 

 

VT-420 Visual ODS Pro

The Visual ODS Pro™ package combines all of the features of the Visual ODS™ package with the features of the VES-3000 Signal Processing option.  The Signal Processing option includes an FFT for analyzing data in either the time or frequency domain, plus waveform cut, copy and paste, and many other signal processing features.

Signal Processing Features:

  • Simultaneous FFT & IFFT on all measurements in a Data Block. The FFT will transform any number of samples, and is not restricted to a power-of-2
  • Integration & differentiation of time or frequency signals
  • Cut, Copy & Paste of time or frequency signals
  • DC Removal of time or frequency signals
  • Sort & Select waveforms
  • Notch & Band windows for removing unwanted data from time or frequency waveforms
  • Force and exponential windows to remove noise and leakage from impulse response measurements
  • A flat top window for obtaining accurate narrow band signal amplitudes
  • A Hanning window for minimizing leakage effects in frequency spectra
  • Calculation of Fourier Spectra, Auto Spectra, PSDs & ODS FRFs from time domain operating data
  • Signal processing includes, Rectangular, Hanning, or Flat Top time domain windows, triggering, linear or peak hold spectrum averaging, and overlap processing
  • ODS FRFs can be calculated either from Auto & Cross Spectra or from Transmissibility’s and reference Auto Spectra
  • Order-tracked ODS’s can be displayed directly from multi-channel Order-tracked response only data
  • Block Math functions include complex scaling, add, subtract, multiply, divide, conjugate, and more
  • Units conversion and scaling between Linear (RMS) and Power (MS)
  • Measurement scaling between Peak, Peak to Peak, and RMS
  • Waveform statistics (Minimum, Maximum, Mean Squared, RMS, Variance, Standard Deviation, Absolute Deviation, Power, Linear Power, Crest Factor, Skew, Kurtosis)

Shape Processing Features:

  • Shape Integration & differentiation
  • Shape Cut, Copy & Paste
  • Sort & Select of shapes and shape components (DOFs)
  • Calculates a shape product, for locating nodal points and lines among all shapes

 

 

VT-570 Visual Modal

The Visual Modal™ package combines all of the features of the Visual ODS Pro™ package with the features of the VES-4000 Basic Modal Analysis option.  The Basic Modal Analysis option provides all of the tools you need for extracting modal parameters from experimental vibration measurements (FRFs). With Visual Modal™ you can identify the frequency, damping & mode shape of the modes of a structure from experimental data.

Modal parameter estimation (curve fitting) is done in three steps; 1) count the number of modes using a Mode Indicator function, 2) estimate the modal frequency & damping for each mode, 3) estimate a modal residue (a mode shape component) for each mode & each measurement.

Modal Analysis Features:

  • Mode Indicators for counting modes. Either a Complex Mode Indicator Function (CMIF) or a Multivariate Mode Indicator Function (MMIF) can be calculated, and all resonance peaks are counted above a scrollable noise threshold
  • Frequency & damping curve fitting. Either the Local or the Global MDOF Orthogonal Polynomial method can be used, with extra polynomial terms to compensate for out-of-band modes
  • Residue curve fitting. Either the MDOF Orthogonal Polynomial method or the SDOF Peak cursor method can be used
  • Quick Fit. Automatically executes all three curve fitting steps with minimal user interaction
  • Frequency & damping estimates are graphically indicated on the Mode Indicator graph
  • A curve fit function is synthesized and overlaid on each measurement to graphically confirm each curve fit
  • Selected measurements and frequency bands can be used to improve modal parameter estimates
  • All modal parameter estimates and curve fitting functions are saved with each measurement
  • FRFs can be synthesized using modal parameters
  • Modal Assurance Criterion (MAC). A bar graph and spreadsheet of the MAC values between all mode shape pairs. If MAC = 1, two shapes are the same.  If MAC < 0.9 two shapes are different.
  • Shape Difference Indicator (SDI). A bar graph and spreadsheet of the SDI values between all mode shape pairs. If SDI = 1, two shapes have the same values. If SDI < 0.9 two shapes have different values
  • Modal Participation. Displays the Real part, Imaginary part, and Magnitude of the modal participation factors that result when a set of shapes is curve fit to another set of shapes.
  • Mode shapes can be re-scaled between Residue and UMM mode shapes
  • Modal parameters can be imported & exported using the Universal File Format (UFF)
  • Mode shapes can be imported from Ansys, Emerson Process Management (CSI), FEMAP, LMS, I-DEAS, NASTRAN, Ono Sokki, Rockwell Automation Emonitor, Spectral Dynamics Star disk files

 

 

VT-550 Visual Modal Pro

The Visual Modal Pro™ package combines the features of the Visual Modal™ package with the features of both the VES-4500 Multi-Reference Modal Analysis and VES-3500 MIMO Modeling & Simulation options.

The Multi-Reference Modal Analysis option includes advanced Multiple Reference curve fitting methods for extracting the modal parameters of closely coupled modes or repeated roots from multiple reference FRF data. This option also includes Stability diagram methods for finding modes in data where resonance peaks cannot be counted on Mode Indicator curves.

The MIMO Modeling & Simulation option includes advanced processing features for calculating multiple outputs from multiple time or frequency inputs, and for performing force path analysis by calculating multiple inputs from multiple outputs.  Multiple Reference FRFs can also be calculated with this option, along with Multiple and Partial Coherence.

Multi-Reference Modal Analysis Features:

  • Mode counting to identify closely coupled modes & repeated roots using either the Multi-Reference Complex Mode Indicator Function (CMIF), or the Multi-Reference Multivariate Mode Indicator Function (MMIF)
  • Curve fitting using the Multiple Reference Orthogonal Polynomial method
  • Multi-Reference Quick Fit. Automatically executes three curve fitting steps (count modes, estimate frequency & damping for each mode, estimate residues for each mode) with minimal user interaction
  • Multi-Reference curve fitting using a Stability diagram and either the Z-Polynomial curve fitting method, the Complex Exponential curve fitting method, or the Alias-Free Polynomial (AF Poly) curve fitting method
  • Stability A graphical display of frequency & damping estimates (poles) in differently colored stable pole groups. All poles are calculated using curve fitting model sizes ranging from 1 to a user-defined maximum
  • Stable Poles A graphical display of poles (frequency & damping estimates) in differently colored stable pole groups
  • Stable Pole Group. A group of solutions on a Stability or Poles diagram that satisfy a user-defined minimum number of poles that lie within user-defined frequency & damping tolerances
  • Shape Complexity Plot. A graphical display of the complex shape components of one or more mode shapes
  • Shape Component Magnitude Ranking. A graphical display of the ordered magnitudes of the shape components of each mode shape
  • Shape Expansion. A set of shapes with many DOFs is curve fit to a set of shapes with few DOFs, to create new shapes with many DOFs in them
  • Poles A graph of the modal frequency & damping estimates (poles) of a set of mode shapes

MIMO Modeling & Simulation Features:

  • MIMO Forced Response: Calculates multiple response time or frequency waveforms (outputs) caused by multiple excitation forces (inputs), using either FRFs or mode shapes to model the system dynamics
  • MIMO Sinusoidal Forced Response. Calculates and displays response (output) shapes caused by multiple sinusoidal excitation (input) forces, using either FRFs or mode shapes to model the system dynamics
  • MIMO Force Path Analysis. Calculates multiple excitation force time or frequency waveforms from multiple response (outputs), using either FRFs or mode shapes to model the system dynamics
  • MIMO FRFs (Transfer functions). These frequency functions can be calculated from multiple excitation (input) and response (output) time waveforms, using Rectangular or Hanning time domain windows, triggering, linear or peak hold spectrum averaging, and overlap processing
  • Multiple and Partial Coherences. These frequency functions can also be calculated together with MIMO FRFs. Multiple Coherence measures the overall contribution of all measured excitation forces (inputs) to each measured response (output), for each frequency. Partial Coherence measures the contribution of each measured excitation force (input) to each measured response (output), for each frequency.
  • MIMO FRFs (Transfer functions) can be calculated from multi-channel Auto & Cross frequency spectra

 

 

VT-960 Visual OMA

The Visual OMA™ package combines all of the features of a Visual Modal™ package with the features of the VES-4700 Operational Modal Analysis option.  For cases where the excitation forces cannot be measured and output-only responses can be acquired, modal parameters can still be extracted from a set of specially processed Cross Spectra or ODS FRFs.

The Operational Modal Analysis option adds special windowing and other features to a Visual Modal™ package, thus providing a complete set of tools for extracting modal parameters from measurements made in any type of testing environment.

Modal parameter estimation (curve fitting) is done in three steps; 1) count the number of modes using a Mode Indicator function, 2) estimate the modal frequency & damping for each mode, 3) estimate a modal residue (a mode shape component) for each mode & each measurement.

Visual OMA™ Features:

  • Deconvolution window. When this window is applied to a set of Cross Spectra or ODS FRFs, operational modal parameters can be extracted from them using FRF-based curve fitting methods
  • Mode shape scaling. A modal model (a scaled set of mode shapes) can be created from a set of output-only operational mode shapes
  • Mode Indicators for counting modes. Either a Complex Mode Indicator Function (CMIF) or a Multivariate Mode Indicator Function (MMIF) can be calculated, and all resonance peaks are counted above a scrollable noise threshold
  • Frequency & damping curve fitting. Either the Local or the Global MDOF Orthogonal Polynomial method can be used, with extra polynomial terms to compensate for out-of-band modes
  • Residue curve fitting. Either the MDOF Orthogonal Polynomial method or the SDOF Peak cursor method can be used
  • Quick Fit. Automatically executes all three curve fitting steps with minimal user interaction
  • Frequency & damping estimates are graphically indicated on the Mode Indicator graph
  • A curve fit function is synthesized and overlaid on each measurement to graphically confirm each curve fit
  • Selected measurements and frequency bands can be used to improve modal parameter estimates
  • All modal parameter estimates and curve fitting functions are saved with each measurement
  • FRFs can be synthesized using modal parameters
  • Modal Assurance Criterion (MAC). A bar graph and spreadsheet of the MAC values between all mode shape pairs. If MAC = 1, two shapes are the same.  If MAC < 0.9 two shapes are different.
  • Shape Difference Indicator (SDI). A bar graph and spreadsheet of the SDI values between all mode shape pairs. If SDI = 1, two shapes have the same values. If SDI < 0.9 two shapes have different values
  • Modal Participation. Displays the Real part, Imaginary part, and Magnitude of the modal participation factors that result when a set of shapes is curve fit to another set of shapes.
  • Modal parameters can be imported & exported using the Universal File Format (UFF)
  • Mode shapes can be imported from Ansys, Emerson Process Management (CSI), FEMAP, LMS, I-DEAS, NASTRAN, Ono Sokki, Rockwell Automation Emonitor, Spectral Dynamics Star disk files

 

 

VT-910 Visual OMA Pro

The Visual OMA Pro™ package combines the features of the Visual Modal Pro™ package with the features of the VES-4700 Operational Modal Analysis option.  For cases where the excitation forces cannot be measured and output-only responses are acquired, modal parameters can still be extracted from a set of specially processed Cross Spectra or ODS FRFs. The Operational Modal Analysis option adds special windowing and other features to the Visual Modal Pro™ package, thus providing a complete set of tools for extracting modal parameters from measurements made in any type of testing environment.

Visual OMA Pro™ Features:

  • Deconvolution When this window is applied to a set of Cross Spectra or ODS FRFs, operational modal parameters can be extracted from them using FRF-based curve fitting methods
  • Mode shape scaling. A modal model (a scaled set of mode shapes) can be created from a set of output-only operational mode shapes
  • Mode counting to identify closely coupled modes & repeated roots using either the Multi-Reference Complex Mode Indicator Function (CMIF), or the Multi-Reference Multivariate Mode Indicator Function (MMIF)
  • Curve fitting using the Multiple Reference Orthogonal Polynomial method
  • Multi-Reference Quick Fit. Automatically executes three curve fitting steps (count modes, estimate frequency & damping for each mode, estimate residues for each mode) with minimal user interaction
  • Multi-Reference curve fitting using a Stability diagram and either the Z-Polynomial curve fitting method, the Complex Exponential curve fitting method, or the Alias-Free Polynomial (AF Poly) curve fitting method
  • Stability A graphical display of frequency & damping estimates (poles) in differently colored stable pole groups. All poles are calculated using curve fitting model sizes ranging from 1 to a user-defined maximum
  • Stable Poles A graphical display of poles (frequency & damping estimates) in differently colored stable pole groups
  • Stable Pole Group. A group of solutions on a Stability or Poles diagram that satisfy a user-defined minimum number of poles that lie within user-defined frequency & damping tolerances
  • Shape Complexity Plot. A graphical display of the complex shape components of one or more mode shapes
  • Shape Component Magnitude Ranking. A graphical display of the ordered magnitudes of the shape components of each mode shape
  • Shape Expansion. A set of shapes with many DOFs is curve fit to a set of shapes with few DOFs, to create new shapes with many DOFs in them
  • Poles A graph of the modal frequency & damping estimates (poles) of a set of mode shape

 

 

VT-710 Visual Acoustics

The Visual Acoustics™ package includes all of the features of the Visual ODS™ package, plus the features of the VES-6000 Acoustics option.  With this package, you can post-process and display in animation Acoustic Intensity, Sound Pressure Level (SPL), Sound Power, and ODS’s from either Octave or Narrow Band measurements.  Vibro-acoustic data (acoustics & vibration), can be displayed on the same structure model, thus allowing you to correlate surface vibration with acoustic field measurements.

Visual Acoustics™ Features:

  • Animated display of vibro-acoustic data (acoustic & vibration)
  • 1/1, 1/3rd, 1/12th, 1/24th octave band measurements are displayed in bar chart format
  • Magnitudes can be displayed in Linear, Log, dB, dB Reference units
  • Acoustic Intensity is calculated from Cross Spectra or time waveforms
  • Sound Power through a surface is calculated from Acoustic Intensity
  • Narrow band can be converted to octave band measurements
  • A, B & C weighting can be applied to narrow band or octave band measurements
  • Noise sources can be ranked in a bar chart based on percentage of overall, dB, or watts.
  • Measurements can be tone-calibrated, using tone magnitude & phase

 

 

VT-740 Visual Vibro-Acoustics

The Visual Vibro-Acoustics™ package combines all of the features of the Visual Modal™ package with the features of the VES-6000 Acoustics option.

The VES-4000 Basic Modal Analysis option in the Visual Modal™ package provides all of the tools you need for extracting modal parameters from experimental vibration measurements (FRFs). With Visual Modal™ you can identify the frequency, damping & mode shape of the modes of a structure from experimental data.

Modal parameter estimation (curve fitting) is done in three steps; 1) count the number of modes using a Mode Indicator function, 2) estimate the modal frequency & damping for each mode, 3) estimate a modal residue (a mode shape component) for each mode & each measurement

With the VES-6000 Acoustics option, you can post-process and display in animation Acoustic Intensity, Sound Pressure Level (SPL), Sound Power, and ODS’s from either Octave or Narrow Band measurements.  Vibro-acoustic data (acoustics & vibration), can be displayed on the same structure model, thus allowing you to correlate surface vibration with acoustic field measurements.

Acoustics Features:

  • Animated display of vibro-acoustic data (acoustic & vibration)
  • 1/1, 1/3rd, 1/12th, 1/24th octave band measurements are displayed in bar chart format
  • Magnitudes can be displayed in Linear, Log, dB, dB Reference units
  • Acoustic Intensity is calculated from Cross Spectra or time waveforms
  • Sound Power through a surface is calculated from Acoustic Intensity
  • Narrow band can be converted to octave band measurements
  • A, B & C weighting can be applied to narrow band or octave band measurements
  • Noise sources can be ranked in a bar chart based on percentage of overall, dB, or watts.
  • Measurements can be tone-calibrated, using tone magnitude & phase

Modal Features:

  • Mode Indicators for counting modes. Either a Complex Mode Indicator Function (CMIF) or a Multivariate Mode Indicator Function (MMIF) can be calculated, and all resonance peaks are counted above a scrollable noise threshold
  • Frequency & damping curve fitting. Either the Local or the Global MDOF Orthogonal Polynomial method can be used, with extra polynomial terms to compensate for out-of-band modes
  • Residue curve fitting. Either the MDOF Orthogonal Polynomial method or the SDOF Peak cursor method can be used
  • Quick Fit. Automatically executes all three curve fitting steps with minimal user interaction
  • Selected measurements and frequency bands can be used to improve modal parameter estimates
  • Frequency & damping estimates are graphically indicated on the Mode Indicator graph
  • A curve fit function is synthesized and overlaid on each measurement to graphically confirm each curve fit
  • All modal parameter estimates and curve fitting functions are saved with each measurement
  • FRFs can be synthesized using modal parameters
  • Modal Assurance Criterion (MAC). A bar graph and spreadsheet of the MAC values between all mode shape pairs. If MAC = 1, two shapes are the same.  If MAC < 0.9 two shapes are different.
  • Modal parameters can be imported & exported using the Universal File Format (UFF)
  • Mode shapes can be imported from Ansys, Emerson Process Management (CSI), FEMAP, LMS, I-DEAS, NASTRAN, Ono Sokki, Rockwell Automation Emonitor, Spectral Dynamics Star disk files

 

 

VT-540 Visual SDM

The Visual SDM™ package combines all of the features of the Visual Modal™ package with the features of the VES-5000 Structural Dynamics Modification option.

Once you have identified and quantified a resonance problem in a machine or structure, the next question is, “How can the structure be modified to fix the problem?”

Visual SDM™ helps you quickly evaluate alternative solutions to resonance problems by adding additional tools to the modal analysis features of a Visual Modal™ package. The Structural Dynamics Modification (SDM) method allows you to examine the effects of a variety of potential structural modifications on the resonances of a structure without actually having to make the physical modifications.

The resonances (modes of vibration) of a machine or structure depend on its physical properties (geometry, density, elasticity, boundary conditions, etc.). Changing the physical properties of a structure by adding modifications such as stiffeners, brackets, tuned absorbers or other modifications, will directly affect its modes. The SDM method uses industry standard finite elements such as springs, masses, dampers, bars, plates, and solids to model the modifications. These modifications, together with the modes of the original (unmodified) structure, are used to calculate the new modes of the modified structure.

In the example shown below, a stiffener was added across the bottom of an aluminum panel. Adding the stiffener replaced the first mode of the structure (a bending mode at 73Hz) with a torsional mode at 94Hz. The torsional mode was the second mode of the original structure but was not affected by the rib stiffener. Without the added stiffener, machinery in the vicinity operating at 4000-4500 RPM would excite the first bending mode of this panel causing it to resonate.  Adding the stiffener not only eliminated the mode at 73Hz, but also eliminated another mode at 143Hz, thus removing a potential resonance problem at 2X RPM as well.

Structural Dynamics Modification Features:

  • Interactive graphical addition of structural modification elements to a structure model
  • All visible FEA elements on a structure model are used by SDM. All hidden elements are ignored
  • Modifications can be modeled using the following FEA elements; Point masses, linear springs and linear dampers, rod and beam elements, triangular and quadrilateral plate elements, tetrahedrons, prisms, and brick solid elements
  • All finite element properties are displayed and edited in property spreadsheets
  • Modal sensitivity analysis. Define a solution space of FEA properties, and calculate new modes that minimize differences with target modal properties
  • Sub-structuring. Two or more substructures can be connected together with FEA elements, and the modes of the combined substructures calculated
  • Tuned absorbers. Multiple mass-spring-damper vibration absorbers can be attached to a structure model, and the new modes of the structure calculated

Modal Analysis Features:

  • Mode Indicators for counting modes. Either a Complex Mode Indicator Function (CMIF) or a Multivariate Mode Indicator Function (MMIF) can be calculated, and all resonance peaks are counted above a scrollable noise threshold
  • Frequency & damping curve fitting. Either the Local or the Global MDOF Orthogonal Polynomial method can be used, with extra polynomial terms to compensate for out-of-band modes
  • Residue curve fitting. Either the MDOF Orthogonal Polynomial method or the SDOF Peak cursor method can be used
  • Quick Fit. Automatically executes all three curve fitting steps with minimal user interaction
  • Frequency & damping estimates are graphically indicated on the Mode Indicator graph
  • A curve fit function is synthesized and overlaid on each measurement to graphically confirm each curve fit
  • Selected measurements and frequency bands can be used to improve modal parameter estimates
  • All modal parameter estimates and curve fitting functions are saved with each measurement
  • FRFs can be synthesized using modal parameters
  • Modal Assurance Criterion (MAC). A bar graph and spreadsheet of the MAC values between all mode shape pairs. If MAC = 1, two shapes are the same.  If MAC < 0.9 two shapes are different.
  • Shape Difference Indicator (SDI). A bar graph and spreadsheet of the SDI values between all mode shape pairs. If SDI = 1, two shapes have the same values. If SDI < 0.9 two shapes have different values
  • Modal Participation. Displays the Real part, Imaginary part, and Magnitude of the modal participation factors that result when a set of shapes is curve fit to another set of shapes.

 

 

VT-560 Visual SDM Pro

The Visual SDM Pro™ package combines all of the features of the Visual Modal Pro™ package with the features of the VES-5000 Structural Dynamics Modification option.

Once you have identified and quantified a resonance problem in a machine or structure, the next question is, “How can the structure be modified to fix the problem?”

Visual SDM Pro™ helps you quickly evaluate alternative solutions to resonance problems by adding additional tools to the modal analysis features of a Visual Modal Pro™ package. The Structural Dynamics Modification (SDM) method allows you to examine the effects of a variety of potential structural modifications on the resonances of a structure without actually having to make physical modifications.

The resonances (modes of vibration) of a machine or structure depend on its physical properties (geometry, density, elasticity, boundary conditions, etc.). Changing the physical properties of a structure by adding modifications such as stiffeners, brackets, tuned absorbers or other modifications, will directly affect its modes. The SDM method uses industry standard finite elements such as springs, masses, dampers, bars, plates, and solids to model the modifications. These modifications, together with the modes of the original (unmodified) structure, are used to calculate the new modes of the modified structure.

In the example shown below, a stiffener was added across the bottom of an aluminum panel. Adding the stiffener replaced the first mode of the structure (a bending mode at 73Hz) with a torsional mode at 94Hz. The torsional mode was the second mode of the original structure but was not affected by the rib stiffener. Without the added stiffener, machinery in the vicinity operating at 4000-4500 RPM would excite the first bending mode of this panel causing it to resonate.  Adding the stiffener not only eliminated the mode at 73Hz, but also eliminated another mode at 143Hz, thus removing a potential resonance problem at 2X RPM as well.

Structural Dynamics Modification Features:

  • Interactive graphical addition of structural modification elements to a structure model
  • All visible FEA elements on a structure model are used by SDM. All hidden elements are ignored
  • Modifications can be modeled using the following FEA elements; Point masses, linear springs and linear dampers, rod and beam elements, triangular and quadrilateral plate elements, tetrahedrons, prisms, and brick solid elements
  • All FEA element properties are displayed and edited in property spreadsheets
  • Modal Sensitivity Analysis. Define a solution space of FEA properties, and calculate new modes that minimize differences with target modal properties
  • Sub-structuring. Two or more substructures can be connected together with FEA elements, and the modes of the combined substructures calculated
  • Tuned absorbers. Multiple mass-spring-damper vibration absorbers can be attached to a structure model, and the new modes of the structure calculated

Multi-Reference Modal Analysis Features:

  • Mode counting to identify closely coupled modes & repeated roots using either the Multi-Reference Complex Mode Indicator Function (CMIF), or the Multi-Reference Multivariate Mode Indicator Function (MMIF)
  • Curve fitting using the Multiple Reference Orthogonal Polynomial method
  • Multi-Reference Quick Fit. Automatically executes three curve fitting steps (count modes, estimate frequency & damping for each mode, estimate residues for each mode) with minimal user interaction
  • Multi-Reference curve fitting using a Stability diagram and either the Z-Polynomial curve fitting method, the Complex Exponential curve fitting method, or the Alias-Free Polynomial (AF Poly) curve fitting method
  • Stability A graphical display of frequency & damping estimates (poles) in differently colored stable pole groups. All poles are calculated using curve fitting model sizes ranging from 1 to a user-defined maximum
  • Stable Poles A graphical display of poles (frequency & damping estimates) in differently colored stable pole groups
  • Stable Pole Group. A group of solutions on a Stability or Poles diagram that satisfy a user-defined minimum number of poles that lie within user-defined frequency & damping tolerances
  • Shape Complexity Plot. A graphical display of the complex shape components of one or more mode shapes
  • Shape Component Magnitude Ranking. A graphical display of the ordered magnitudes of the shape components of each mode shape
  • Shape Expansion. A set of shapes with many DOFs is curve fit to a set of shapes with few DOFs, to create new shapes with many DOFs in them
  • Poles A graph of the modal frequency & damping estimates (poles) of a set of mode shapes.

MIMO Modeling & Simulation Features:

  • MIMO Forced Response: Calculates multiple response time or frequency waveforms (outputs) caused by multiple excitation forces (inputs), using either FRFs or mode shapes to model the system dynamics
  • MIMO Sinusoidal Forced Response. Calculates and displays response (output) shapes caused by multiple sinusoidal excitation (input) forces, using either FRFs or mode shapes to model the system dynamics
  • MIMO Force Path Analysis. Calculates multiple excitation force time or frequency waveforms from multiple response (outputs), using either FRFs or mode shapes to model the system dynamics
  • MIMO FRFs (Transfer functions). These frequency functions can be calculated from multiple excitation (input) and response (output) time waveforms, using Rectangular or Hanning time domain windows, triggering, linear or peak hold spectrum averaging, and overlap processing
  • Multiple and Partial Coherences. These frequency functions can also be calculated together with MIMO FRFs. Multiple Coherence measures the overall contribution of all measured excitation forces (inputs) to each measured response (output), for each frequency. Partial Coherence measures the contribution of each measured excitation force (input) to each measured response (output), for each frequency.
  • MIMO FRFs (Transfer functions) can be calculated from multi-channel Auto & Cross frequency spectra

 

 

VT-920 Visual FEA Model Updating

The Visual FEA Model Updating™ package combines the features of a Visual SDM Pro™ package with the features of the VES-8000 FEA Model Updating option. With the FEA Model Updating option you can create an FEA model by adding FEA elements to the same model that is used to display ODS’s and mode shapes in animation.

The normal or complex FEA modes of the structure can be calculated from the FEA model. This option includes a library of FEA elements, including springs, masses, dampers, rods, bars, plates, and three types of solid elements. It also includes the FEA Assistant for quickly populating any structure model with FEA elements.

This package also includes the VES-5000 Structural Dynamics Modification option.

Once you have identified and quantified a resonance problem in a machine or structure, the next question is, “How can the structure be modified to fix the problem?”

The Structural Dynamics Modification (SDM) method allows you to examine the effects of a variety of potential structural modifications on the resonances of a structure without actually having to make physical modifications.

The resonances (modes of vibration) of a machine or structure depend on its physical properties (geometry, density, elasticity, boundary conditions, etc.). Changing the physical properties of a structure by adding modifications such as stiffeners, brackets, tuned absorbers or other modifications, will directly affect its modes. The SDM method uses the same industry standard finite elements as the FEA Model Updating option to model the modifications.  Either EMA (Experimental Modal Analysis) modes or FEA modes can be used with SDM to model the dynamics of the un-modified structure.

FEA Model Updating Features:

  • FEA Materials List. Contains material properties (elasticity, Poisson’s ratio, density)
  • FEA Properties List. Contains properties that can be assigned to FEA elements
  • FEA Assistant. Populates a geometric model with FEA elements.
  • Calculates Normal Modes for models with no damping
  • Calculates Complex Modes for models with damping
  • Calculates stress & strain for an FEA model deformed with ODS data.
  • Point matching between FEA and EMA models
  • FEA Model Updating. Define a solution space of FEA properties, and calculate new FEA mode shapes which minimize differences with EMA modal parameters
  • Imports & exports FEA models in a variety of popular third party disk file formats

Structural Dynamics Modification Features:

  • Interactive graphical addition of FEA modification elements to a structure model
  • All visible elements on a structure model are used by SDM and Experimental FEA. All hidden elements are ignored
  • Modifications can be modeled using the following FEA elements; Point masses, linear springs and linear dampers, rod and beam elements, triangular and quadrilateral plate elements, tetrahedrons, prisms, and brick solid elements
  • All finite element properties are displayed and edited in property spreadsheets
  • Modal Sensitivity Analysis. Define a solution space of FEA properties, and calculate new modes that minimize differences with target modal properties
  • Sub-structuring. Two or more substructures can be connected together with FEA elements, and the modes of the combined substructures calculated
  • Tuned absorbers. Multiple mass-spring-damper vibration absorbers can be attached to a structure model, and the new modes of the structure calculated

 

 

VT-950 Visual STN

The Visual STN™ package combines the features of the Visual ODS™ package with the features of all of the following Visual Engineering Series options;

  • VES-3000 Signal Processing
  • VES-3500 MIMO Modeling & Simulation
  • VES-4000 Basic Modal Analysis
  • VES-4500 Multi-Reference Modal Analysis
  • VES-4700 Operational Modal Analysis
  • VES-5000 Structural Dynamics Modification
  • VES-6000 Acoustics
  • VES-8000 Experimental FEA